Under questioning by Mr Brandis today at a Senate estimates committee, AFP deputy commissioner Peter Drennan revealed they knew in November 2012 the man was wanted on terrorism charges and informed the Department of Immigration and Citizenship immediately, but he stayed in the low-security facility at Inverbrackie until April this year.

The department says the "suspicions" were only confirmed in February and "appropriate security was maintained around this client and increased when necessary".

Detainees and a guard in front of transportable units at the Inverbrackie detention centre, near Woodside.Source:News Limited

The man arrived in Australia by boat in May 2012 and is understood to have been moved to Inverbrackie about July. In April this year he was moved to the Villawood high-security detention centre in Sydney.

ASIO director-general David Irvine conceded a "clerical or some other mistake" led to the man initially being cleared.